Young Xehanort

Young Xehanort is one of the main antagonists (alongside Ansem and Xemnas) of Kingdom Hearts 3D: Dream Drop Distance. Doning a black cloak, this young man is also a young Master Xehanort who traveled through time. In the game, he invades the dream realm and taunts Sora and Riku as they take their Mark of Mastery exam; particularly the former, holding information about the hearts that reside in his that even he doesn't know of. He was given the power to travel through time by his future Heartless (Ansem).

Story (spoiler)

Before Birth by sleep

Young Xehanort lived most of his life on Destiny Islands, until the day came when he was visited by a mysterious hooded man, whom is actually his future Heartless Ansem. Upon meeting with him, Ansem reveals to him his future.

Trivia

Due to the difficulty of time travel, when Young Master Xehanort travels back to his own time period after the events of the game he forgets everything that took place.